A text-book of physiology, for medical students and physicians . the absolute power of a frogs muscle of 1 square centimetercross-area is estimated at from kilogram to 3 kilograms, whilethat of a human muscle of the same size is estimated by Hermannat kilograms. Taken as a whole, the human muscle is a bettermachine for work, but it seems possible, although exact figures arelacking, thai the absolute power of the muscles of some insectsreckoned for the same unit of cross-area would be much greaterthan in human muscle. COMPOUND OR TETANIC CONTRACTIONS. Definition of Tetanus —When a musc
A text-book of physiology, for medical students and physicians . the absolute power of a frogs muscle of 1 square centimetercross-area is estimated at from kilogram to 3 kilograms, whilethat of a human muscle of the same size is estimated by Hermannat kilograms. Taken as a whole, the human muscle is a bettermachine for work, but it seems possible, although exact figures arelacking, thai the absolute power of the muscles of some insectsreckoned for the same unit of cross-area would be much greaterthan in human muscle. COMPOUND OR TETANIC CONTRACTIONS. Definition of Tetanus —When a muscle receives a series ofrapidly repeated stimuli it remains in a condition of conlTaction aslong :i- ilf stimuli are sent, in or until it loses its irritability from the effecl of fatigue. A contraction of this character is describedcompound contraction or tetanus. If the stimuli follow each THE PHENOMENON OF CONTRACTION. 41 other with sufficient rapidity the muscle shows no external sign ofrelaxation in the intervals between stimuli, and if its contractions. Fig. 19.—Analysis of tetanus. Experiment made upon the gastrocnemius muscle of afrog to show that by increasing the rate of stimulation the contractions, at first separate(1), fuse more and more through a series of incomplete tetani (2, 3, 4) into a complete tetanus(5) in which there is no indication, so far as the record goes, of a separate effect for eachstimulus. are recorded upon a kymographion by means of an attached levera curve is obtained such as is shown at 5 in Fig. 19. A con-traction of this character is described as a complete tetanus. If, 42 THE PHYSIOLOGY OF MUSCLE AND XERYE. however, the rate of stimulation is not sufficiently rapid the mus-cle will relax more or less after each stimulus and its recordedcurve, therefore, will present the appearance shown in 1, 2, 3, and4 of Fig. 19. A tetanus of this character is described as an incom-plete tetanus. It is obvious that according to the rate of stimu-lation
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